1. Field of the Invention
The present invention relates to a signal line circuit device.
2. Description of the Related Art
Patent Reference 1 discloses a laminated resonator in which a line conductor is provided between layers of dielectric insulators, and a ground conductor is provided on the outer layer. A method of controlling the frequency of this type of laminated resonator by trimming the line conductor is already known.
However, conventionally the line conductor is covered with a layer of insulator, meaning that in order to trim the line conductor, the line conductor must first be exposed at one side surface of the laminated structure, which requires the entire side surface to be cut away.
FIGS. 14A and 14B are diagrams showing a conventional example, wherein a signal line is disposed on the surface of an insulator layer on which circuit elements are formed.
In this diagram, a signal line 6 is formed on the surface of a dielectric layer 4, and a ground line 8 is formed on the lower surface of the dielectric layer 4. Furthermore, although not shown in the diagram, circuit elements such as semiconductor elements and/or passive elements are disposed on the surface of the dielectric layer 4, and a molded resin 14 then covers these circuit elements.
In this conventional configuration, the signal line 6 is covered with the dielectric layer 4 and the molded resin 14, meaning that in order to trim the signal line 6, either the entire side surface of the device must be cut away, as indicated by the dashed line in FIG. 14A, or alternatively, a portion of the molded resin 14 must be removed as shown in FIG. 14B, thereby exposing the signal line 6 and enabling the trimming operation to be performed, and the removed molded resin 14 must then be replaced. If trimming of the signal line 6 is conducted using the method shown in FIG. 14A, a positional constraint arises in that the signal line 6 must be positioned close to the side surface to be trimmed. On the other hand, if trimming of the signal line 6 is conducted using the method shown in FIG. 14B, then in order to achieve the partial removal of the molded resin 14, a molding die that is capable of providing the required opening must be used, and following trimming, the opening must then be filled with molding resin, which makes this method costly and time-consuming.
3. Related Art List
Japanese Patent Laid-Open Publication No. Hei 6-224606